V. Foltin et al. Drive Towards Environmentally Friendly Inhibitors for Natural Gas Hydrate... The Holistic Approach to Environment 4(2014)4, 145-151 Page 145 ISSN 1848-0071 553.981+544.475=111 Recieved: 2013-11-12 Accepted: 2014-01-15 Original scientific paper DRIVE TOWARDS ENVIRONMENTALLY FRIENDLY INHIBITORS FOR NATURAL GAS HYDRATE FORMATION PREVENTION VIKTOR FOLTIN, JÁN RAJZINGER¹ Slovak University of Technology in Bratislava, Faculty of Mechanical Engineering, Institute of Mathematics and Physics, Slovakia ¹Slovak University of Technology in Bratislava, Faculty of Mechanical Engineering, Institute of Thermal Power Engineering, Slovakia e-mail: viktor.foltin@stuba.sk This work summarizes methods for prevention of gas pipeline clogging by natural gas hydrate formation – with emphasis on development of environmentally friendly hydrate inhibitors. The work highlights advantages and disadvantages of current solutions and encourages future studies on new type of inhibitors based on ice-structuring proteins. Key words: natural gas hydrate, hydrate inhibitors, flow assurance, antifreeze proteins, ice-structuring proteins, Rhagium mordax. Nastojanja oko ekološki prihvatljivih inhibitora za sprečavanje hidrata prirodnog plina. Ovaj rad sažima metode za prevenciju začepljenja plinovoda uvjetovanu stvaranjem hidrata plina - s naglaskom na razvoj ekološki prihvatljivih inhibitora hidrata. Rad naglašava prednosti i nedostatke postojećih rješenja i potiče buduće studije o novoj vrsti inhibitora utemeljenoj na led-strukturirajućim proteinima. Ključne riječi: hidrat prirodnog plina, inhibitori hidrata, osiguranje protoka, antifriz proteini, led-strukturirajući proteini, Rhagium mordax. INTRODUCTION Natural gas hydrate is a clathrate of natural gas guest molecule embedded in a cage of water host molecules formed at high pressure and low temperature conditions. Research on natural gas hydrates focuses on several areas: i) extraction of hydrates from permafrost and ocean bottom regions where enormous reserves of hydrates are present and can become a fuel of the future, ii) cheap, dense and safe methane storage in form of natural gas hydrate, iii) use of hydrates as a media for natural gas and CO 2 sequestering, and, iv) prevention of hydrate formation and clogging of gas pipelines and distribution systems [1, 2, 3, 4, 5]. This work summarizes recent advances in hydrate formation inhibition in gas pipelines. Several factors can help to reduce hydrates presence in gas pipelines, for example, i) maintaining temperature and pressure that is unfavorable for clathrate formation, ii) adding inhibitor chemicals to break hydrogen bonds of host water cages and stop or slowdown hydrate formation. As presented elsewhere water (a polar molecule, with their extraordinary properties allowed